Acute Exacerbation of COPD

Audience This case is targeted to emergency medicine residents of all levels. Introduction Shortness of breath (SOB) is one of the top ten most common chief complaints seen in the Emergency Department, accounting for close to 10% of presenting complaints.1 An acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a frequent culprit, accounting for roughly 15.4 million visits and 730,000 hospitalizations per year.2 The diagnosis of treatment of mild to moderate AECOPD can be relatively uncomplicated; however, multiple factors can increase the complexity of management and pose additional challenges that the emergency physician (EP) must be prepared for. Severe AECOPD can necessitate the need for both Non-invasive positive pressure ventilator (NIPPV) such as bi-level positive airway pressure (BiPAP) as well as emergent intubation. Furthermore, managing the ventilator settings in patients with an AECOPD is far from routine, requiring an intricate understanding of pulmonary physiology.3 Educational Objectives By the end of this simulation, learners will be able to (1) assess for causes of severe shortness of breath, (2) manage severe COPD exacerbation by administering appropriate medications, (3) identify worsening clinical status and initiate NIPPV, (4) assess the causes of hypoxia after establishing endotracheal intubation and, (5) identify indication for needle decompression and perform chest tube thoracostomy. Educational Methods This simulation was conducted with a high-fidelity mannequin with a separate low fidelity chest tube mannequin that allowed for hands-on practice placing a chest tube. A total of 16 PGY-1 residents participated in the simulated patient encounter. Research Methods Following the simulation and debrief session, all residents were sent a Likert scale survey via surveymonkey.com to assess the educational quality of the simulation. The survey contained the following questions; 1) Overall, this simulation was realistic and could represent a patient presentation in the Emergency Department, 2) Overall, the case contained complexity that challenged me as a learner, 3) This case helped to expand my medical knowledge, 4) I feel more confident in diagnosing and treating AECOPD, 5) I feel more confident in recognizing the indications for NIPPV and intubation, 6) This simulation offered an opportunity to improve my procedural skills, 7) I feel more confident in setting up the ventilator, 8) I feel more confident in addressing ventilator alarms. Results Following the simulation and debrief session, all the participants (n=16), were provided a survey to assess the educational quality of the simulation. There were a total of 12 respondents and a hundred percent of them agreed or strongly agreed that the case contained complexity that challenged them. All of the respondents agreed that the simulation case was realistic and that the case helped expand their medical knowledge. Furthermore, all the learners agreed or strongly agreed that the case helped them in improving their procedural skills. Discussion This case combines a mixture of high fidelity and medium fidelity components to encompass both clinical knowledge and procedural skills. This case is effective in expanding beyond the basic approach to managing an AECOPD patient and forces learners to address clinical deterioration, escalate airway interventions, manage ventilator settings, and address ventilator alarms, including placement of a chest tube. Residents commented that this case was very realistic and particularly challenging because it highlighted gaps in their clinical knowledge and procedural skills. Residents were most challenged by identifying when to escalate care as well as how to manage ventilator settings in AECOPD patients. Topics Acute exacerbation COPD, intubation, positive pressure ventilation, ventilator alarms, chest tube thoracostomy.


Linked objectives and methods:
This case begins with the patient presenting with shortness of breath and a history of COPD. The learners will have to perform a primary assessment, identify signs of respiratory distress, and start initial interventions (objective #1). They will have to obtain further history and identify the likely diagnosis of AECOPD and then initiate disease specific treatment (objective #2). The patient will progress to respiratory failure and require escalation of interventions (objective #3 and #4). The ventilator high peak pressure alarm will trigger as the patient deteriorates, requiring the learner to evaluate for causes of post-intubation hypoxia and high peak pressures (objective #5). Learners will need to ultimately perform needle decompression and chest tube thoracostomy (objective #6).
Recommended pre-reading for instructor : We strongly recommend reviewing the following articles and videos about managing ventilator alarms:

Results and tips for successful implementation:
This simulation was designed for emergency medicine residents to improve their resuscitation skills by managing a decompensating acute exacerbation of COPD that requires intubation and subsequently develops a tension pneumothorax and requires needle decompression and chest tube thoracostomy. The case was performed in a high-fidelity simulation setting using an additional low fidelity modified chest tube thoracostomy mannequin to simulate chest tube placement.
Some tips for successful implementation of this simulation include: • Create teams of 3-4 learners, preferably with mixed levels of training to balance experience levels with management of severe AECOPD and ventilator management. • Before the beginning of the case, we recommend the learners assign roles to help the case run smoothly. This simulation was designed and implemented during the 2022-2023 academic year. It was conducted with first-year emergency medicine residents in a total of four separate inperson sessions. The debrief session was conducted in two large groups immediately after the simulation. All learners were from the same residency program.
Following the simulation and debrief session, participants (n=16), were provided a survey to assess the educational quality of the simulation, as well as open ended feedback. There were a total of 12 respondents (75% of participating residents). Figure 1 shows 100% of them agreed or strongly agreed that the case contained complexity that challenged them.  shows that all of them agreed that the simulation case was realistic. All of them agreed or strongly agreed that the case expanded their medical knowledge ( Figure 3). In addition, the last figure showed that the learners agreed or strongly agreed that the case helped them in improving their procedural skills ( Figure 4).   The most common suggestions for improvement surrounded utilization of NIPPV and managing ventilator alarms. One resident suggested pairing this case with another simulation that demonstrates the difference in ventilator settings based on disease process. Given the depth and complexity of ventilator

Case Description & Diagnosis (short synopsis):
A 57-year-old male with congestive heart failure (CHF), coronary artery disease (CAD), and COPD presents with SOB. His vitals are initially hypoxic and tachycardic, and he is ill-appearing with respiratory distress. While in the emergency department (ED) he becomes more altered, and his respiratory effort diminishes as he begins to tire out. As the case progresses, he fails BiPAP secondary to agitation, and ultimately requires intubation. A short while after being placed on the ventilator, the peak pressure alarm sounds, and the patient will become hypoxic. The patient has developed a tension pneumothorax and requires needle decompression and chest tube placement. The patient will be admitted to the intensive care unit (ICU) with the diagnosis of hypercapnic and hypoxic respiratory failure secondary to acute exacerbation of COPD.  Background and brief information: A 57-year-old male is brought in by emergency medical services (EMS) to the ED at a tertiary care center for "shortness of breath."

Initial presentation:
The patient is brought in from home by EMS for progressive shortness of breath for the past two days. The patient is ill-appearing, but able to answer questions in short sentences. He is tachypneic, hypoxic, and tachycardic.
How the scene unfolds: A 57-year-old male is brought in by EMS for shortness of breath. The patient is in respiratory distress and only able to answer in short sentences. If prompted by learners, EMS is available to provide the following information: patient has been complaining of progressive difficulty breathing over past two days in the context of running out of his home inhaler medications. Learners should recognize the signs of respiratory distress. Patient should be placed on the monitor, given 2 large bore IVs, and placed on supplemental oxygen. Learners should start empiric treatment for COPD exacerbation; they can defer to pharmacy for dosing if needed.
Laboratory studies, EKG, CXR should be ordered. Point of care testing including glucose and ABG can be ordered. Initial COPD treatment should be initiated. Bedside ultrasound can be performed to evaluate for cardiac contractility (acute coronary syndrome, congestive heart failure) and lung fields (B-lines congestive heart failure).
After primary and secondary survey are completed, the simulation nurse will inform the learners of declining mental status and decreased respiratory rate, which should prompt the learner to escalate care. Patient should be placed on BiPAP; learners should provide settings. Patient continues to be agitated pulling off the mask. Learners can initially try moderate sedation; however, patient continues to pull at mask, ultimately requiring intubation. Learners should provide ventilator settings. Regardless of settings given, shortly after being placed on the ventilator, the peak pressure alarm sounds, and the patient becomes hypoxic. Learners should consider inspiratory hold to evaluate for plateau pressure, disconnecting ETT, obstruction of ETT, pulmonary US for pneumothorax. Patient is diagnosed with tension pneumothorax and requires needle decompression and chest tube placement. Following chest tube placement, his hypoxia improves, and he is stable for admission to the ICU.  • History of present illness: He has been feeling progressively short of breath for past two days. • Past medical history: COPD, congestive heart failure, coronary artery disease • Past surgical history: None • Patient's medications: "Inhalers" (Budesonide and formoterol), aspirin 81mg, "water pill" (furosemide)

Acute Exacerbation of COPD
Pearls: In addition to the treatments outlined above, it is important to remember that patients with COPD have chronic mild hypoxia. When assessing and treating these patients, we must avoid excess oxygen because this can cause diffuse pulmonary vasodilation, which leads to worsening ventilation-perfusion mismatching. For patient with AECOPD, inhaled oxygen should be titrated to target an oxygen saturation of 88-92%. 4

General treatment of acute COPD exacerbation:
• Albuterol is a beta-2 adrenergic receptor agonist and acts to relax the bronchial smooth muscle. It also inhibits the release of immediate hypersensitivity mediators from cells, especially mast cells. Albuterol can be given intermittently 2.5-5mg every 20minutes for a total of three dose per hour or may be given in a continuous nebulizer 10-15mg over one hour. 4 • Ipratropium is an acetylcholine antagonist and facilitates decreased contraction of the smooth muscles as well as decreased airway secretions. Ipratropium is commonly given in conjunction with albuterol. Typical dosing is 0.5mg and maybe given three times per hour. 4 • Steroids are a mainstay of AECOPD treatment. They reduce treatment failure, shorten hospital length of stay, improve lung function, and reduce dyspnea. The ideal route of administration and dosing of steroids has been debated. Either oral or IV options are available. Typical dosing for an AECOPD includes oral prednisone 40-60mg, 125 methylprednisolone IV. 4 • Antibiotics should be given to all patients presenting with AECOPD, regardless of whether there is a clear infiltrate on chest radiograph. Patients with COPD are often chronically colonized by a variety of organisms, and therefore the goal of antibiotic therapy is to suppress this bacterial growth situation. For most patients, narrow spectrum antibiotics are fine, such as azithromycin or doxycycline. 1,4 Optimizing oxygenation: When treating a patient with hypoxemia or respiratory distress, it is important to determine whether they need assistance with ventilation, oxygenation, or both. In general, oxygenation is controlled by PEEP and FiO 2 , whereas ventilation is controlled via tidal volume and respiratory rate. As providers in the emergency department, we have multiple modalities at our disposal, but it is imperative that we understand the benefits and limitations of each. 5 • Nasal cannula: Typically, nasal cannula is set to a flow rate between 1-6L/min, administering 24-44% fraction of inspired oxygen (FiO 2 ), assisting with oxygenation. This modality does not offer any positive end expiratory pressure (PEEP) and requires patients to ventilate entirely on their own. 5 • Non-rebreather mask (NRB): Typically, NRB is set to a flow rate between 10-15L/min, administering 60-95% FiO 2 , assisting with oxygenation. NRB is unable to provide 100% FiO 2 secondary to air leak between the patient's face and the mask. This modality does not offer any PEEP and requires patients to ventilate entirely on their own. 5 • High flow nasal cannula (HFNC): Typically, HFNC is set to a flow rate between 30-60L/min, administering 21-99% FiO 2 , assisting with oxygenation. Theoretically, HFNC can provide 100% FiO 2 ; however, this requires no air entry through the mouth, which will be 21% FiO 2. This modality does offer a small degree of positive end expiratory pressure (PEEP), usually 0-5 cmH 2 O. It does not assist with ventilation. 5 • Non-invasive positive pressure ventilation (NIPPV): There are two main types of NIPPV, Bi-level positive airway pressure (BiPAP) and continuous positive airway pressure (CPAP). As the name implies, BiPAP allows a set inspiratory pressure (IPAP) and a set expiratory pressure (EPAP). The difference between these pressures, the pressure support, helps to assist with tidal volume and improve ventilation. CPAP has one set continuous pressure, which correlates to PEEP, and therefore does not affect ventilation. NIPPV can also provide up to 100% FiO 2, assisting with oxygenation. 3 BiPAP can be applied in patients with any of the following: respiratory acidosis with pH < 7.3 despite treatments, severe dyspnea with increased work of breathing and accessory muscle use and persistent hypoxemia with oxygen therapy. Some of the contraindications for BiPAP include respiratory or cardiac arrest, hemodynamic instability, inability to use mask, excessive secretions, high risk of aspiration, altered mental status and uncooperative patient. Initial settings usually begin with IPAP at 8-10cm H 2 O and EPAP at 4-5cm H 2 O and the settings can be titrated according to the clinical status and patient's response. 3 Additionally, continuous nebs may be given when utilizing BIPAP. Unfortunately, as in this case, patients may not tolerate BiPAP secondary to agitation or anxiety. Given its significant impact on decreasing mortality and need for intubation in COPD exacerbations, it is not unreasonable to trial moderate sedation with ketamine or dexmedetomidine in patients not tolerating BiPAP. Ventilator settings and high-pressure alarms: Ventilator settings for a patient with an AECOPD should follow a lung protective strategy, being mindful to the risks of lung overinflation and subsequent pneumothorax. Given this, typically ventilator settings for patients intubated for AECOPD are as follows: tidal volume 6-10 ml/kg, respiratory rate 10-14 breaths/minute, PEEP 0-5 cm H 2 O, FiO 2 100%. Of greatest importance is the respiratory rate and tidal volume because these variables dictate ventilation, the primary problem in AECOPD. Furthermore, patients with COPD already have hyperinflated lungs due to chronic alveoli distention and air retention. Over-inflation due to a high tidal volume or fast respiratory rate can lead to breath stacking, an extremely dangerous consequence in COPD patients. 3

DEBRIEFING AND EVALUATION PEARLS
Once a patient is placed on a ventilator, the force required to deliver a breath can be thought of in terms of pressure. There are two systems of pressure involved, the pressure to overcome the resistance of the airways and the pressure required to distend the lungs and chest wall, also known as compliance. The sum of these two pressures gives us our total peak pressure. When there are high peak pressures, it is imperative to determine whether the elevated pressure is from the resistance of the airway or the compliance of the lung. To do this, we must measure the plateau pressure, which is measured by performing an inspiratory hold on the ventilator at end inspiration. A high plateau pressure suggests a decrease in compliance and therefore a primary lung problem, whereas a normal plateau pressure suggests an airway resistance problem, which could originate from the anatomical airway of our patient all the way back to the ventilator machine itself. [6][7][8] A simple algorithm to follow when assessing high peak pressures is as follows: